1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to providing a signal processing apparatus and a method thereof, and more particularly, to providing a signal processing apparatus for adjusting and outputting levels of input signals and a method thereof.
2. Description of the Related Art
Digital televisions are a representative form of audio/video apparatus which display movies on a screen. Digital televisions divide received broadcast signals into video signals and audio signals, and processes the video signals and audio signals separately.
FIG. 1 illustrates an audio processor of a digital television for processing separated audio signals. In FIG. 1, a conventional audio processor comprises an audio input unit 10, a lip-sync compensation unit 20, an auto volume control (AVC) unit 30, and an audio output unit 40.
The lip-sync compensation unit 20 delays audio signals input from the audio input unit 10 in order to synchronize video signals and audio signals.
The AVC unit 30 automatically adjusts levels of audio signals and outputs the adjusted audio signals to the audio output unit 40. Specifically, the AVC unit 30 automatically adjusts the level of a currently input audio signal by referring levels of previously input audio signals.
The AVC unit 30 automatically adjusts levels of audio signals so as to appropriately output audio signals by automatically adjusting volume when input of audio signals is changed, for example, when a channel is changed.
The lip-sync compensation unit 20 embeds a memory which is necessary to delay audio signals. The AVC unit 30 also has a memory device which stores previously input audio signals in order to adjust the level of a currently input audio signal.
Since the lip-sync compensation unit 20 and the AVC unit 30 require memory devices, the audio processor requires many memory devices, resulting in increased manufacturing costs.
Moreover, at the time when the channel is changed, the AVC unit 30 does not have previously input audio signals. Therefore, the result of audio volume control of audio signals input to the audio processor is not satisfactory initially when the channel is changed.